If you are doing research in temperate regions, then you may choose flower crops like Sterilitzia sp (Bird of paradise) and Hydrangea sp....U can go for different biotechnological aspects of such crops on which more works is not done till date...So u can explore these areas....

Let's try to address multiple stress tolerance studies under protected cultivation , not too many attempts, you will find ...

You can do some works on development of diseases resistant flower variety for the commercial growers.